Coupling of magnetoresistance switching and glassy magnetic state at the metal-insulator transition in Ruddlesden-Popper manganite Ca4Mn3O10

JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS

卷:511

Article

Periyasamy, Manimuthu^1,2  Fjellvag, Oystein S.^1,3  Fjellvag, Helmer¹  Sjastad, Anja Olafsen¹ 

[1] Univ Oslo, Ctr Mat Sci & Nanotechnol, Dept Chem, POB 1033, N-0315 Oslo, Norway

[2] Hebrew Univ Jerusalem, Appl Phys Dept, Quantum Nano Engn Lab, IL-9190401 Jerusalem, Israel

[3] Inst Energy Technol, Dept Neutron Mat Characterizat, POB 40, N-2027 Kjeller, Norway

关键词: Ruddlesden-Popper;    Manganites;    Synchrotron X-ray diffraction;    Magnetic properties;    Electron transport;    Magneto-resistance;   

DOI  :  10.1016/j.jmmm.2020.166949

来源: Elsevier

【 摘 要 】

Electronic phase separation is a frequent ingredient of the physics of manganites for which the colossal magnetoresistance (CMR) phenomenon is at debate. We investigate the switchable magnetoresistance (MR) effect of the Ruddelsden-Popper (RP) oxide Ca4Mn3O10 (CMO), which shows a metal-to-insulator transition (MIT) at 70 K (T-MIT). The static (DC) and dynamic (AC) magnetic susceptibilities of CMO indicate an unusual magnetic phase coexistence below the Neel temperature (T-N) i.e., at T-MIT, which we describe as a glassy magnetic behavior. Furthermore, by means of synchrotron X-ray diffraction, we observed a structural anomaly directly associated with the MIT. Hence, the onset of glassiness correlates with a slight structural distortion. Interestingly, CMO displays a large positive magneto-resistance (PMR) effect (up to 550% at 4 K) in the metallic state below T-MIT, while a small negative magneto-resistance (NMR) effect (-3.5% at 112 K) in the insulating region above T-MIT. At T-MIT, the PMR switches to NMR behavior. PMR is probably induced via enhancing the exchange interaction by localization of itinerant moment resulting in formation of magnetic polarons, whereas NMR is possibly due to reduced electron-spin scattering. This appears to be a special type of magnetoresistance, different from regular observations, and may open a new avenue in searching for exotic phenomena in manganese-based CMR materials.

【 授权许可】

Free